Apparatus for connecting electric appliances

ABSTRACT

The device provides a signal to an electronic appliance and is used in a system including a plurality of electronic appliances connected in series so that they can transmit and receive information and control signals amongst each other, with the transmission and reception of the information signals being controlled by a control apparatus. The system includes a preceding apparatus and a succeeding apparatus connected in series with the preceding apparatus. The device includes a first terminal that transmits and receives information and control signals to and from the preceding apparatus, and a second terminal that transmits and receives information and control signals to and from the succeeding apparatus. The second terminal also receives a predetermined control signal from the succeeding apparatus. The predetermined control signal indicates whether the succeeding apparatus is connected to a terminal of the preceding apparatus. The device also includes a switching unit and a processor.

This is a continuation of application Ser. No. 07/728,985, filed on Jul.12, 1991, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for connecting electronicappliances, a control apparatus and an address setting method suitablefor collectively controlling a plurality of electronic appliances suchas audio visual appliances or the like.

2. Description of the Prior Art

In a data transmission system according to the RS-232C standard, it isknown that operation of audio and visual appliances (hereinafter simplyreferred to as AV appliances) can be controlled by a computer, such as apersonal computer or the like.

According to the RS-232C standard, various data are transmitted andreceived in a manner so that the computer and the AV appliances areplaced in a one-to-one relation. Therefore, in the case of a system inwhich a plurality of AV appliances are controlled by a single computer(control apparatus), the computer side must include an RS-232C standardterminal corresponding to each of the AV appliances, or specialchange-over switches for switching the data transmission to therespective AV appliances must be employed. Accordingly, there is thenthe problem that the system cannot be used well for various purposesbecause the number of terminals or the switching ability of thechange-over switches (the number of the change-over switches) must bechanged with the increase or decrease of the AV appliances.

It is also proposed that a plurality of AV appliances can be controlledby utilizing a bus line used in a so-called local network system. Thisproposal, however, has the following disadvantages. For example, whentwo or more different data are simultaneously transmitted, detection ofsuch data becomes complicated (troublesome) and the transmissionprocessing of such data also becomes complicated, which unavoidablymakes the interface housed within the AV appliance large-sized andexpensive.

Further, it is conventional to connect a plurality of controlledapparatus (electronic appliances such as AV appliances) in series (in adaisy chain fashion) to a control apparatus such as a controller or thelike. The respective AV appliances are controlled in operation by thiscontroller. In such a system, addresses are allocated (set) to therespective AV appliances and a command signal for commanding operationof the particular AV appliance is transmitted to the particular AVappliance together with the address from the controller. Accordingly,addresses to allocated to the respective AV appliances must be madedifferent.

In order to remove this disadvantage, it is proposed that addresses areallocated to different categories of AV appliances (e.g., categories oftelevision receiver, a video tape recorder, a television camera and soon). This proposal, however, has the disadvantage that, if two videotape recorders are provided, then addresses for identifying these twovideo tape recorders cannot be allocated.

It has also been proposed that respective AV appliances be provided withdip switches or the like, so that addresses can be set by manipulatingthe dip switches. However, this proposal makes the arrangement of the AVapparatus complicated and addresses must be set in a manual fashion. Asa consequence, if the number of AV appliances is increased, then theaddressing setting becomes considerably troublesome.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide animproved apparatus for connecting electronic appliances in which theaforementioned shortcomings and disadvantages encountered with the priorart can be eliminated.

More specifically, it is an object of the present invention to providean apparatus for connecting electronic appliances in which, even ifthere is only single RS-232C standard terminal, a plurality ofelectronic appliances can be controlled by single control apparatus in asystematized fashion (i.e., collectively).

It is another object of the present invention to provide an addresssetting method in which the controlled apparatus can be set to differentaddresses only by supplying address setting signals to the controlledapparatus from a control apparatus.

As an aspect of the present invention, an electronic applianceconnection device is described for providing a signal to an electronicappliance and adapted for use in a system including a plurality ofelectronic appliances connected in series so as to transmit and receiveinformation and control signals to and from each other. The systemadditionally includes a control apparatus for collectively controllingtransmission and reception of the information signals. The plurality ofelectronic appliances and the control apparatus include a precedingapparatus and a succeeding apparatus connected in series with thepreceding apparatus. The electronic appliance connection device includesa means for providing a signal to the electronic appliance, a firstterminal means for receiving the information and control signals fromthe preceding apparatus, and for transmitting the information andcontrol signals to the preceding apparatus, and a second terminal meansfor receiving the information and control signals and a predeterminedcontrol signal from the succeeding apparatus, and for transmitting theinformation and control signals to the succeeding apparatus. A switchingunit is connected to the first terminal means. A first line is connectedbetween the switching unit and the second terminal means. A second lineis connected between a processor and the switching unit, wherein theswitching unit selectively connects the first terminal means with one ofthe first line and the second line. The processor receives thepredetermined control signal, and includes means for supplying switchcontrol signals to the switching unit in response to the presence orabsence of the predetermined control signal. The switching unitselectively connects the first terminal means with one of the first lineand the second line in response to the switch control signals, so thatinformation signals supplied to the switching unit from the secondterminal means are supplied through the switching unit to the firstterminal means when the predetermined control signal is present at theprocessor, and so that information signals on the second line aresupplied through the switching unit to the first terminal means when thepredetermined control signal is not present at the processor.

According to the apparatus for connecting electronic appliances of thepresent invention, under the condition that the plurality of electronicappliances are connected in series so as to transmit and receiveinformation signals and predetermined control signals, the transmissionand reception of the information signals can be collectively controlledby a desired control apparatus.

Further, on the basis of the existence or absence of a predeterminedcontrol signal generated from the control signal generating unit, it isdetermined whether or not another connecting apparatus is connected tothe connecting apparatus. If another connecting apparatus is notconnected, then the information signal transmitted to the connectingapparatus of the final stage can be fed back to the control apparatuswhich initially outputs the information signal or to another controlapparatus by the switching operation of the switching unit.

As a second aspect of the present invention, an address setting methodis provided, in which a plurality of controlled apparatus which cantransmit and receive various signals between them and a desired controlapparatus are connected in series to a control apparatus, varioussignals transmitted to the controlled apparatus of the final stagethrough the respective controlled apparatus are fed through a signalline back to the control apparatus and particular addresses n are set tothe respective controlled apparatus. According to this address settingmethod, when an address setting signal is supplied to a desiredcontrolled apparatus from the control apparatus, the address settingsignal is sequentially processed in a predetermined manner by a desiredcontrolled apparatus and a controlled apparatus connected to thesucceeding stage of the desired controlled apparatus.

Therefore, the processing for allocating particular addresses to therespective controlled apparatus is introduced into the predeterminedprocessing executed in the respective controlled apparatus, wherebydifferent addresses are allocated to the respective controlledapparatus.

The above and other objects, features, and advantages of the presentinvention will become apparent in the following detailed description ofillustrative embodiments thereof to be read in conjunction with theaccompanying drawings, in which like reference numerals are used toidentify the same or similar parts in the several views.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a schematic diagram showing an overall arrangement of anembodiment of an apparatus for connecting electronic appliancesaccording to the present invention;

FIG. 2 is a schematic diagram showing an electrical arrangement of amain portion of the apparatus shown in FIG. 1;

FIG. 3 is a schematic diagram showing an arrangement of a packet signalused in an embodiment of the present invention;

FIG. 4 is a flowchart to which references will be made in explaining theprocedure executed by a central processing unit (CPU) of the connectingapparatus an embodiment of the present invention;

FIG. 5 is a schematic diagram showing an arrangement of a system used inan embodiment of an address setting method according to the presentinvention;

FIG. 6 is a schematic diagram showing an arrangement of a command usedin the above embodiment;

FIG. 7 is a schematic diagram showing an arrangement of a command usedin another embodiment of the present invention;

FIG. 8 is a schematic diagram showing an arrangement of a system inwhich three video tape recorders are connected in series; and

FIG. 9 is a schematic diagram showing a main portion of the system shownin FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in detail and, initially to FIG. 1, anapparatus 1 to which the present invention is applied will be describedhereinafter.

As shown in FIG. 1, the apparatus 1 includes first and second terminals3 and 5. Through the first terminal 3, signals are transmitted andreceived between the apparatus 1 and a desired control apparatus 40(which can be a personal computer). Signals are transmitted between theapparatus 1 and a second apparatus 1 via a cable 30. Through theterminal 3 of the second apparatus, signals are transmitted and receivedbetween the first apparatus 1 and the second apparatus 1 via the cable30 and the terminal 5 of the first apparatus.

Each apparatus 1 is connected, for example, to a video tape recorder(VTR) 50, a video tape recorder having a built-in camera 60, or anotherelectronic appliance 70 by means of a cable 20, or the apparatus 1 ishoused in a video tape recorder 80.

The apparatus 1 are connected serially, and the video tape recorder 50and other electronic appliances are collectively controlled by thepersonal computer 40 via the apparatus 1.

Let us describe the case in which electronic appliance 70 and the videotape recorder 80 are controlled by the personal computer 40 in theconnected states shown by dashed lines 10 in FIG. 1.

FIG. 2 shows an electrical arrangement of a main portion of theapparatus shown in FIG. 1. Referring to FIG. 2, in the first and secondterminals 3 and 5, data signal input and output ports 3a, 3b, 5a, 5b andcontrol signal input and output ports 3c through 3f and 5c through 5fare provided in parallel to one another.

A data signal from the personal computer 40 is supplied to the inputport 3b, from which it is delivered to a port (SIN) 9b of amicrocomputer 9 mainly made of a central processing unit (CPU) 9A or thelike and is then stored in a buffer 9B.

The data signal is supplied in the form of a packet signal and thepacket signal is formed of a set of at its head a transmission address,a reception address (each apparatus 1 has the transmission and receptionaddresses), a command (control content), various data and a terminator,in that order, as shown in FIG. 3.

Referring back to FIG. 2, the packet signal stored in the buffer 9B isprocessed by the CPU 9A in processing manner which will be describedlater and is delivered from the port (SOUT) 9a.

A switching unit 11 is interposed between the ports 9a and 3a so as toselectively connect the output port 3a to port 9a or port 5b.

The switching unit 11 short-circuits the ports 3a and 5b when a secondapparatus 1 is connected to the rear stage of the first apparatus 1, andshort-circuits the ports 3a and 9a when the second apparatus 1 is notconnected to the rear stage of the first apparatus 1.

More specifically, when the second (succeeding) apparatus 1 is connectedto terminal 5 of the first apparatus 1, a voltage of high level (e.g.,5v) is applied to the port 3f of the succeeding apparatus 1 and thisvoltage is supplied through the port 3f of the succeeding apparatus andport 5e of the first apparatus 1 to the port 9g of microcomputer 9 (ofthe first apparatus 1) so that microcomputer 9 allows a switchchange-over control signal to be produced from the port 9f under thecondition such that the input voltage applied to the port 9g is high inlevel. Thus, the switching unit 11 of the first apparatus 1 is changedin position (control means) so that the ports 3a and 5b areshort-circuited by the above control signal (condition 1).

When the succeeding apparatus 1 is not connected to terminal 5 of thefirst apparatus 1, the voltage applied to the ports 5e and 9g of thefirst apparatus is low in level so that the switching unit 11short-circuits the ports 3a and 9a (condition 2). In that event, thepacket signal from the port 9a is delivered to the port 5a through asignal line L and is also delivered to the port 3a through a signal line"1" diverged from the signal line L.

When the voltage at the port 9g is high in level (i.e., when thesucceeding apparatus 1 is connected to terminal 5 of the first apparatus1), the ports 5d and 9d are short-circuited by a switching unit 13,while when that voltage is low in level (i.e., when the succeedingapparatus 1 is not connected to terminal 5 of the first apparatus 1),the ports 3d and 9d are short-circuited by the switching unit 13. In thelatter case, the control signal input from the port 3d of the apparatus1 of the final stage is supplied through the ports 9d, 9c and 3c to theport 5d of the apparatus 1 of the preceding stage.

Further, this control signal is fed through the ports 5d, 9d, 9c and 3cin the apparatus 1 of the preceding stage back to the personal computer40. The control signal thus fed back to the personal computer 40 is usedto determine whether or not each apparatus 1 is ready for receiving datafrom the personal computer 40.

An interrupt processing control signal is asserted by the firstapparatus 1 from the port 3e and latched in a port (INT) of the personalcomputer 40. Further, this control signal diverged from the port 3e islatched through the ports 5f (of the first apparatus 1) and 3e (of thesucceeding apparatus 1) to the port 9e of the succeeding apparatus 1.

In the thus constructed first apparatus 1 (the apparatus 1 of thepreceding stage), the packet signal from the personal computer 40 isinput from the port 3b and stored in the buffer 9B, in which it isprocessed in a predetermined processing manner and then input to theport 3b of the apparatus 1 of the succeeding stage through the ports 9aand 5a and the cable 30.

In case the apparatus 1 of the succeeding stage is the apparatus 1 ofthe final stage, then the packet signal from the port 9a (of theapparatus 1 of the final stage) is input through the port 3a and thecable 30 to the port 5b of the apparatus 1 of the preceding stage andfed through the port 3a back to the personal computer 40.

More specifically, when the personal computer 40 derives the packetsignal, this packet signal is temporarily stored in the buffer 9B ofeach microcomputer 9, in which it is processed by the CPU 9A in apredetermined processing manner, if necessary, and then transmitted tothe apparatus 1 of the succeeding stage. The packet signal transmittedto the apparatus 1 of the final stage is again fed back to the personalcomputer 40.

Accordingly, by performing a predetermined operation in the personalcomputer 40, the packet signal is transmitted to all the apparatus 1and, if necessary, then the apparatus 1 controls operation of theelectronic appliance 70 and the video tape recorder 80 in accordancewith the packet signal.

The procedure executed by the CPU 9A in accordance with the packetsignal stored in the buffer 9B will be described below with reference toa flowchart forming FIG. 4.

Referring to FIG. 4, following the Start of operation, it is determinedin the next decision step 100 whether or not the voltage at the port 5dis high in level. If the voltage at the port 5d is high in level asrepresented by a YES at decision step 100, then the processing proceedsto step 120, whereat the switching unit 11 is placed in the condition 1(i.e., the ports 3a and 5b are short-circuited). If the voltage at theport 5d is low in level as represented by a NO at decision step 100,then the processing proceeds to step 140, whereat the switching unit 11is placed in the condition 2 (i.e., the ports 3a and 9a areshort-circuited).

Then, it is determined in the next decision step 160 whether or not apacket signal is input from the port 9b. If the packet signal issupplied from the port 9b, then the processing proceeds to step 180 theinput packet signal is stored in the buffer 9B.

It is determined in the next decision step 200 whether or not thereception address is its own address (address of the apparatus 1itself). If the reception address is apparatus's own address asrepresented by a YES at decision step 200, then the processing proceedsto step 220, whereat the command of the packet signal is executed. Ifthe electronic appliance 70 is the video tape recorder, then operationcontrol such as starting the recording operation or the like isperformed.

If the reception address is not the apparatus's own address asrepresented by a NO at decision step 200, then the processing proceedsto the next decision step 240. It is determined in decision step 240whether or not any command having a priority over the command from thepersonal computer 40 must be issued to another apparatus 1 from theapparatus 1. If such command must be issued to another apparatus 1 asrepresented by a YES at decision step 240, then the command(transmission command) is output from the port 9a and the packet signalfrom the personal computer 40 is output at steps 280 and 260.

As described above, according to this embodiment, the packet signalinput from the personal computer 40 is sequentially latched in eachrespective apparatus 1 and each respective apparatus 1 is provided witha microcomputer 9 for controlling the operation of electronic appliance70 or video tape recorder 80 (or another appliance) so that, even whenthe personal computer 40 is provided with only one RS-232C standardterminal, a plurality of electronic appliances are collectivelycontrolled as a system via the serially connected apparatus 1.

Further, when the number of electronic appliances is increased, thenmerely by connecting additional apparatus 1, the electronic appliancesincluding the increased electronic appliances are all controlled as asystem. This enables the system to be conveniently reconfigured for usein a variety of applications.

Furthermore, since the packet signal is temporarily stored in the buffer9B and the priority order of the packet signals to be transmitted to theapparatus 1 of the succeeding stage is identified, any trouble that hasoccurred in the data transmission can be detected and avoided by anapparatus of simple arrangement, and the manufacturing cost of theapparatus 1 can be also reduced.

Incidentally, the apparatus 1 itself may be utilized as the source(desired control apparatus) which transmits the packet signal and,depending on the arrangement of the packet signal, all the apparatus 1(or electronic appliances controlled by the apparatus 1) may be utilizedas the source which transmits the packet signal, thus making it possibleto construct a so-called multi-master system using the inventivehardware.

As will be understood from the above description, in the apparatus forconnecting electronic appliances according to the present invention,under the condition that the plurality of connecting apparatus areconnected in series so as to transmit and receive a packet signal and apredetermined control signal, the transmission and reception of thepacket signal can be collectively controlled by the desired controlapparatus.

Further, on the basis of the existence or absence of the predeterminedcontrol signal generated from the control signal generating unit, it isdetermined whether or not other connecting apparatus are connected tothe connecting apparatus. If no succeeding connecting apparatus isconnected, then the information signal transmitted to the connectingapparatus of the final stage can be fed back to the control apparatuswhich initially outputs the information signal or to another controlapparatus by the switching operation of the switching unit.

Accordingly, even when the control apparatus is provided with only oneRS-232C standard terminal, the signal output from the control apparatusis sequentially input to the connecting apparatus, whereby therespective electronic appliances are collectively controlled by thecontrol apparatus through the connecting apparatus.

Furthermore, when more electronic appliances are connected, moreconnecting apparatus may be provided, which can cope with the expandedsystem readily.

An embodiment of an address setting method according to the presentinvention will be described next with reference to the drawings.

FIG. 5 schematically illustrates the system to which the presentinvention is applied.

As FIG. 5 shows, controlled apparatus (television receiver 300, videotape recorder "A" 500, video tape recorder "B" 700, and video camera900) are serially connected to a controller (control apparatus) 100A.Each controlled apparatus houses a transmitting and receiving apparatus10 to transmit and receive a signal between it and the controller 100Aor other controlled apparatus.

Transmitting and receiving apparatus 10 is mainly formed of amicrocomputer or the like. The apparatus 10 housed, for example, in VTRA500 performs a predetermined processing on the basis of transmitted dataor the like, transmitting processed data to the VTRB 700 and alsoperforms control processing, such as reproducing operation and recordingoperation of the VTRA 500, etc.

Controller 100A, television receiver 300, VTRA 500, VTRB 700, and videocamera 900 are sequentially connected through two-way communicationlines L1, L2, L3, and L4, and the output signal of the video camera 900is fed through communication lines L1, L2, L3, and L4 back to thecontroller 100A.

The apparatus 10 are serially connected in sequence as described aboveand the electronic appliances such as the television receiver 300 or thelike are collectively controlled by the controller 100A via theapparatus 10 provided in the respective electronic appliances.

Let us now consider the case such that VTRB 700 and video camera 900 arecontrolled by the controller 100A in the connected state shown inFIG. 1. At that time, the arrangement and operation of each apparatus 10is exactly the same as those of apparatus 1 shown in FIG. 2.Accordingly, by performing a predetermined operation in the controller100A, a packet signal is transmitted to each apparatus 10 and relevantones of apparatus 10 drive VTRB 700 and video camera 900 in accordancewith the packet signal, if necessary.

The system of FIG. 5 is constructed as described above, and a method forsetting an address to each of the controlled appliances will bedescribed below.

In the FIG. 5 embodiment, we shall first explain the case that theaddress is not set in the initial state. In this case, if the addressof, for example, television receiver 300 is understood by the controller100A side, then a command (in the form of a packet signal) may betransmitted to that address.

As is understood from FIG. 6, a broadcast command (command "B.C."occupying area A of FIG. 6) is used to access address in order totransmit the following data (including the address setting commandoccupying area B) to all controlled apparatus. A command (the addressvalue command occupying area C) is used in order for an apparatus 10 toset its own address to a value n.

If the apparatus 10 sets its own address to the value n, then thecontent of the area C is changed to a value (n+N) (where N is a numberpredetermined by the system) and the command is transferred to thecontrolled apparatus of the next stage (predetermined processing).

Accordingly, if n=1 and N=1, then television receiver 300, VTRA 500,VTRB 700 and video camera 900 are sequentially set to address 1, address2, address 3, and address 4.

In that case, since the command for setting the address to the value 5is fed from apparatus 10 of video camera 900 back to controller 100A,the controller 100A can know the number of the controlled apparatus(value 5-value 1=value 4) on the basis of that command (value 5).

If all the controlled apparatus have the same address in the initialmode, not the broadcast command but the above address is designated(i.e., the content of the area A is employed as the address value) andthe command may be transmitted.

As described above, according to this embodiment, after the command issupplied from the controller 100A to the television receiver 300,different addresses are sequentially set in the respective controlledapparatus by the appliance 10. Thus, the addresses can be set veryeasily.

We shall next describe the method for setting the address such that theaddress of k'th controlled apparatus is set to value n (with referenceto FIG. 7). Since the address is not set in an controlled apparatus inwhich address need not be set, this address setting method is useful forcontrolling the television receiver 300 and the VTRA 500.

As will be understood from FIG. 7, the command includes a device number(k-1) (which occupies area D) associated with the designated controlledapparatus.

If the content of the area D is value "0", then each of the apparatus 10identifies that the command transmitted is its own command. If thecontent of the area D is not "0", then each of the apparatus 10transfers data in which the content of the area D is added with (-1) tothe controlled apparatus of the next stage as the content of the area D.

Accordingly, when such data is transferred (k-1) times, the desiredcontrolled apparatus (k'th controlled apparatus) is specified and theaddress of that controlled apparatus is set to the value n.

Further, since the address setting data is transmitted to the controller100A from the controlled apparatus 100 in which the address is set, itis possible to confirm the address setting and the controlled apparatusin which the address is not set.

According to the address setting method of this embodiment, the addresssetting is performed a time corresponding to the number of thecontrolled apparatus.

As described above, according to this embodiment, since the desiredcontrolled apparatus is set to a desired address only by transmittingthe command thereto from the controller 100A, the address settingoperation can be made easier.

In the aforementioned two embodiments, since the content of theprocessing (i.e., how to change the address n or the like) done by theapparatus 10 can be set at the controller 100A side, various addresssetting methods become possible.

Furthermore, the apparatus 10 may be utilized as the controller 100A.

As will be understood from the above-mentioned description, according tothe address setting method of the present invention, when the addresssetting signal is supplied to the desired controlled apparatus from thecontrol apparatus, the address setting signal is sequentially processedin a predetermined manner by the controlled apparatus and the controlledapparatus connected to the succeeding stage of the desired controlapparatus.

Therefore, the processing for allocating particular addresses to therespective controlled apparatus is introduced into the predeterminedprocessing executed in the respective controlled apparatus, wherebydifferent addresses are allocated to the respective control apparatus.That is, the address can be set by the simple operation of the controlapparatus.

Let us now consider the case such that editing is performed by utilizinga system in which three video tape recorders 1A, 1B and 1C whose signallines for control signal are serially connected are controlled by acontroller 10 (as shown in FIG. 8).

In this case, a reset signal from the controller 10 is sequentially andserially transmitted through communication lines D₁, D₂, and D₃ to thevideo tape recorders 1A, 1B and 1C. From the video tape recorder 1C,such reset signal is fed through a communication line D4 back to thecontroller 10.

FIG. 9 shows an arrangement of the video tape recorder 1A. As shown inFIG. 9, the video tape recorder 1A is comprised of a VTR unit 3, a timer(i.e., time elapse measuring means) 5, a control unit 7 for controllingoperation of the video tape recorder 1A or the like, and a communicationapparatus 9 which performs the transmission and reception of varioussignals between it and the external controller 10 such as a personalcomputer or the like via a communication bus L.

Timer 5 has a resolution of, for example, about a two-hundredth of asecond and is arranged such that it is reset to time 0 by the resetsignal transmitted from the controller 10 via the communication bus L tooutput a time in which a reset time is time 0 during a time period of atleast several tens of seconds.

The timer 5 may be implemented using either hardware including a quartzoscillator, or software mainly formed of a microcomputer or the like.

The control unit 7 is mainly formed of a microcomputer or the like sothat, when supplied with a time and an operation command (forcontrolling operation of the VTR unit 3) from the controller 10, thecontrol unit 7 executes the command at the above time. The control unit7 is a control means.

Further, when supplied with a command such as a time code or the likefor outputting recording position information of a recording medium(magnetic tape or the like) from the controller 10, the control unit 7reads (i.e., detects) and outputs the recording position information.Simultaneously, the control unit 7 outputs the read time (output of thetimer 5) to the controller 10. Therefore, the control unit 10 is alsoserved as a recording position information outputting means.

The procedure in which editing is performed by utilizing the video taperecorders 1A, 1B shown in FIG. 8 will be described next. In thisprocedure, video tape recorder 1A performs the reproduction and thevideo tape recorder 1B performs the recording. Furthermore, thesynchronization (i e., horizontal and vertical synchronization) of thevideo signal system between the video tape recorders 1A, 1B isestablished similarly to the prior art.

In order to start the reproduction and the recording at the same time,the timer 5 is reset and a command signal indicative of "start playbackat time T" is transmitted to the video tape recorder 1A. Also, a commandsignal indicative of "start recording at time T" is transmitted to thevideo tape recorder 1B.

Thereafter, the control unit 7 causes the VTR unit 3 to start thereproduction (or recording) at the time T.

If extra time is required in the start of reproduction and/or recordingdue to the mechanical arrangement or the like, then the time T may bedesignated in anticipation of such extra time (preparation time).

Accordingly, the time T may be selected to be longer than a sum total oftime of the time in which the controller 10 transmits the reset signal,the time in which the controller 10 transmits the command signal to thetwo video tape recorders 1A and 1B, and the preparation time.

When the video tape recorders 1A and 1B are operated in synchronism witheach other, the displacement between time codes (recording positioninformation) must be checked. To this end, the respective timers 5 arereset by the controller 10 and a command (inquiry) for causing the videotape recorder to transmit the time code to the controller 10 is suppliedto the video tape recorder 1A. Then, the video tape recorder 1A reads atime code Ca and transmits the time code Ca and a read-out time Ta tothe controller 10.

In a like manner, since a time code Cb and a time Tb are transmitted tothe controller 10 from the video tape recorder 1B, the controller 10 canunderstand how much the video tape recorder 1B is advanced from thevideo tape recorder 1A from a time standpoint.

Further, when data at the portion succeeding to the time code C of thevideo tape recorder 1A is recorded by the video tape recorder 1B duringthe video tape recorder 1A reproduces the pre-roll portion while thevideo tape recorder 1B is in the recording standby mode, the timer 5 isreset initially.

Then, the transmission of the time code is commanded to the video taperecorder 1A by the controller 10 and the video tape recorder 1Atransmits the time code Ca and the read time Ta to the controller 10.

Accordingly, when a command signal indicative of "start recording attime (Ta+C-Ca)" is transmitted to the video tape recorder 1B from thecontroller 10, then the control unit 7 of the video tape recorder 1Bcauses VTR unit 3 to start the recording operation at that time.

As described above, the apparatus for connecting electronic appliancesof this embodiment includes the timer 5 which is reset by the controller10, and the control unit 7 which performs the designated control at thedesignated time.

Therefore, high synchronization accuracy (accuracy of the timer 5),necessary for editing or the like, is obtained regardless of the speedof the command signal output from the controller 10 and the informationprocessing speed in the controller 10.

For example, if timer 5 is formed of a quartz oscillator, the operationtime of the timer is several tens of seconds after the timer is reset sothat the resolution of the timer can be adjusted so as to fall withinseveral microseconds with ease. As a consequence, the synchronizationaccuracy also can be controlled so as to fall within 1V.

Further, if the time T is designated in anticipation of the operationresponsiveness at the video tape recorder 1A side, then it becomespossible to avoid synchronization error caused due to the responsivenessof the video tape recorder 1A.

Furthermore, the control unit may be included within other appliancessuch as an audio tape recorder or the like, and the appliances forsupplying video and audio signals to the control unit may be a varietyof AV appliances, electronic musical instruments, etc.

As will be understood from the above description, the control apparatusaccording to the present invention includes a time elapse measuringmeans in which the time elapse measurement is started by the resetsignal. The time elapse measured by the time elapse measuring means isutilized as the absolute time and the operation of the control apparatusis controlled in accordance with that time.

Also, the recording position information on the record medium is outputtogether with the detected time.

Accordingly, when the operation of the recording apparatus (which can bea video tape recorder or the like) is controlled by an external controlapparatus, by merely matching the time points (i.e., inputting the resetsignal), the desired operation command can be executed at the desiredtime by the control apparatus.

As a result, the operation of the control apparatus can be controlledwith high accuracy independently of transmission rate of various datatransmitted and received between the control apparatus and the externalcontrol apparatus and the data processing speed of the external controlapparatus.

In addition, if the operation time is determined in a way to account forthe responsiveness of the control apparatus, then it becomes possible toavoid the synchronization displacement due caused to due theresponsiveness of the control apparatus.

Having described the preferred embodiments of the invention withreference to the accompanying drawings, it is to be understood that theinvention is not limited to those precise embodiments and that variouschanges and modifications thereof could be effected by one skilled inthe art without departing from the spirit or scope of the novel conceptsof the invention as defined in the appended claims.

What is claimed is:
 1. A connection apparatus for providing a signal toan electronic appliance and adapted for use in a system including apreceding apparatus connected in series with the connection apparatus,and a succeeding connection apparatus connected in series with theconnection apparatus, wherein the connection apparatus is connected soas to transmit and receive information signals between the precedingapparatus and the succeeding connection apparatus, wherein the precedingapparatus is a member of a set consisting of a control apparatus forcollectively controlling transmission and reception of the informationsignals and a preceding connection apparatus, the connection apparatuscomprising:a first terminal means for receiving the information signalsfrom the preceding apparatus, and for transmitting the informationsignals to the preceding apparatus; a second terminal means forreceiving the information signals and a predetermined control signalfrom the succeeding connection apparatus, and for transmitting theinformation signals to the succeeding connection apparatus, wherein thepredetermined control signal indicates that the succeeding connectionapparatus is connected to the second terminal means; a switching unitconnected to the first terminal means; a processing means for providingsaid signal; a first line connected between the switching unit and thesecond terminal means; a second line connected between the processingmeans and the switching unit, wherein the switching unit selectivelyconnects the first terminal means with one of the first line and thesecond line; and a third terminal means connecting the processing meanswith the electronic appliance.
 2. A connection apparatus according toclaim 1, wherein the processing means receives the predetermined controlsignal, and includes means for supplying switch control signals to theswitching unit in response to the presence or absence of thepredetermined control signal, and wherein the switching unit selectivelyconnects the first terminal means with one of the first line and thesecond line in response to the switch control signals, so thatinformation signals supplied to the switching unit from the secondterminal means are supplied through the switching unit to the firstterminal means when the predetermined control signal is present at theprocessing means, and so that information signals on the second line aresupplied through the switching unit to the first terminal means when thepredetermined control signal is not present at the processing means, andalso including a third line connected between the processing means andthe second terminal means, for transmitting signals from the processingmeans through the second terminal means to the succeeding connectionapparatus.
 3. A connection apparatus according to claim 1, wherein saidpreceding apparatus is said control apparatus, and said controlapparatus is a computer.
 4. A connection apparatus according to claim 1,wherein each of the information signals is a packet signal.
 5. Aconnection apparatus according to claim 1, wherein the precedingapparatus is said control apparatus, and each of the information signalsincludes a control signal for controlling said control apparatus.